Cascade Layers in Depth: Taming Third-Party CSS
Cascade layers let you control which styles win regardless of specificity. Here is how I structure them to keep third-party CSS in check. Before cascade layers, controlling style priority meant managing specificity and source order. Third-party libraries loaded after your styles could override them with higher-specificity selectors, and your only recourse was!important or refactoring. I spent two weeks on a project fighting Bootstrap's specificity, adding!important to everything, and creating a mess that took months to clean up. Cascade layers would have solved it in one line. Cascade layers are the most significant change to the CSS cascade since specificity itself. They let you declare explicit priority levels that outrank specificity entirely. I want to go deep on how they work, the gotchas I hit, and the layer architecture I use in production. How Layers Affect the Cascade When you declare layers, styles in later-declared layers always win over styles in earlier-declared layers, regardless of specificity. Within a layer, normal cascade rules apply. specificity and source order determine the winner. Unlayered styles always win over layered styles, which is the most important detail to remember. @layer reset, base, framework, components, utilities; This single declaration…